(Reuters) - Intercept Pharmaceuticals Inc said on Sunday its experimental drug for primary biliary cirrhosis, obeticholic acid (OCA), was effective in a third late-stage clinical trial and that the results set the stage for the company to file for marketing approval.

The findings come roughly two months after a clinical trial of OCA in patients with nonalcoholic steatohepatitis was halted early because the drug was working better than expected. (The news sent the company's shares up 281%).

The latest trial, known as POISE, indicates that OCA "clearly produced clinically meaningful improvements" in primary biliary cirrhosis, said Professor Frederik Nevens, chairman of the department of hepatology at the University of Leuven in Belgium and the lead investigator on the trial.

At both a 10 mg dose and a 5 mg dose titrated to 10 mg, OCA met the trial's primary endpoint of achieving a reduction in serum alkaline phosphatase (ALP) from baseline and a normal bilirubin level after 12 months of therapy, the company said.

The proportion of patients meeting the POISE primary endpoint was 10% in the placebo group, 47% in the 10 mg OCA group and 46% in the 5-10 mg OCA group in an intention to treat analysis.

The placebo group experienced a mean decrease in ALP from baseline of 5%, compared to a significant mean decrease of 39% in the 10 mg OCA dose group and 33% in the 5-10 mg OCA titration group.

Intercept stated that both OCA dose groups met pre-specified secondary endpoints of improvements in other liver function parameters, including GGT, ALT, AST and total bilirubin.

Nevens said in a statement that a significant proportion of patients fail to be adequately helped by existing treatments and that new therapies are needed to prevent their disease from progressing to cirrhosis and liver failure.

"I believe that the POISE data indicate OCA will provide a meaningful clinical improvement in these patients," he said.